1. Field of the Invention
The present invention relates to a transmission capacity control device for a traction-transmission-type power transmission apparatus. More particularly, the invention relates to a traction transmission capacity control device in which a reference point of a traction transmission capacity control operation performed by the transmission capacity control device can be set always precisely regardless of whether or not there are manufacturing dimension errors or variations.
2. Background Information
As a power transmission apparatus, for example, a traction transmission type disclosed in Japanese Unexamined Patent Application Publication No. 2002-349653 is known. In a traction-transmission-type power transmission apparatus proposed in this Japanese Patent Publication, a first roller and a second roller are radially pressed and are brought into contact with each other, and power transmission (traction transmission) is performed due to frictional contact between these rollers.
In the above type of power transmission apparatus, traction transmission capacity control may be necessary in which the traction transmission capacity, that is, the traction transmission capacity at a portion at which the first roller and the second roller are radially pressed and are brought into contact with each other, responds to instructed transmission driving power.
Concerning this traction transmission capacity control, the above mentioned Japanese Patent Publication has proposed that a radial-direction mutual pressing force between the rollers is automatically set to be a traction transmission capacity responding to transmission torque.